Resource utilization of hazardous gypsum sludge in oxidation smelting of lead concentrate

Abstract

Gypsum sludge, a hazardous waste generated by the non-ferrous smelting industry, presents a significant challenge for disposal and utilization. To investigate the feasibility of substituting gypsum sludge for limestone as a flux for smelting, the effects of calcium sulfate (CaSO₄) and smelting conditions on oxygen-rich smelting of lead concentrate were studied. The interaction between CaSO₄ and sulfides facilitates the conversion of CaSO₄ into CaO, which is crucial for slag formation. The order of the influence of sulfide minerals on the conversion of CaSO₄ is pyrite > sphalerite > galena. When using gypsum sludge exclusively as the calcium source, under optimal conditions with a CaO/SiO₂ mass ratio of 0.8, an FeO/SiO₂ mass ratio of 1.2, a melting temperature of 1150 °C, an oxygen flow rate of 1.3 L/min, the recovery rates of Pb and Zn in the lead-rich slag reached 85.01% and 95.69%, respectively, with a sulfur content of 2.65 wt%. The As content in the smelting slag obtained by reduction smelting was 0.02 wt%. Resource utilization of gypsum sludge in lead smelting is a feasible method.

Keywords

gypsum sludge / calcium sulfate / resource utilization / smelting

References

[1] Yu Y, Li Y-k, Hu J-h, et al. An all-in-one strategy for resource recovery and immobilization of arsenic from arsenic-bearing gypsum sludge [J]. Chemosphere, 2022, 296: 134078

[2] Yao L-w, Min X-b, Xu H, et al. Physicochemical and environmental properties of arsenic sulfide sludge from copper and lead-zinc smelter [J]. Transactions of Nonferrous Metals Society of China, 2020, 30(7): 1943-1955

[3] Guo X-y, Chen Y-l, Wang Q-m, et al. Copper and arsenic substance flow analysis of pyrometallurgical process for copper production [J]. Transactions of Nonferrous Metals Society of China, 2022, 32(1): 364-376

[4] Pan Z-c, Jiao F, Qin W-q, et al. Research progress on comprehensive utilization of flue gas desulfurization gypsum and gypsum slag in smelting industry [J]. The Chinese Journal of Nonferrous Metals, 2022, 32(5): 1391-1402 (in Chinese)

[5] Chai L-y, Ke Y, Min X-b, et al. Separation and recovery of ZnS from sulfidized neutralization sludge via the hydration conversion of CaSO₄ into bulk CaSO₄·2H₂O crystals [J]. Separation and Purification Technology, 2015, 154: 76-81

[6] Zhang T-f, Liu W, Han J-w, et al. Selective separation of calcium from zinc-rich neutralization sludge by sulfidation roasting and HCl leaching [J]. Separation and Purification Technology, 2021, 259: 118064

[7] Mittal A, Rakshit D. Utilization of cement rotary kiln waste heat for calcination of phosphogypsum [J]. Thermal Science and Engineering Progress, 2020, 20: 100729

[8] Xue W-p, Twenda C, Alam M S, et al. Experimental study on seepage characteristics and stress sensitivity of desulfurization gypsum based concrete under triaxial stress [J]. Journal of Materials Research and Technology, 2023, 24: 6425-6437

[9] Zhao J, Su H, Zuo H-b, et al. The mechanism of preparation calcium ferrite from desulfurization gypsum produced in sintering [J]. Journal of Cleaner Production, 2020, 267: 122002

[10] Shao S, Ma B-z, Wang X, et al. Nitric acid pressure leaching of limonitic laterite ores: Regeneration of HNO₃ and simultaneous synthesis of fibrous CaSO₄·2H₂O by-products [J]. Journal of Central South University, 2020, 27(11): 3249-3258

[11] Zeng C-x, Guan Q-j, Sui Y, et al. Kinetics of nitric acid leaching of low-grade rare earth elements from phosphogypsum [J]. Journal of Central South University, 2022, 29(6): 1869-1880

[12] Liu D-g, Min X-b, Ke Y, et al. Co-treatment of flotation waste, neutralization sludge, and arsenic-containing gypsum sludge from copper smelting: Solidification/stabilization of arsenic and heavy metals with minimal cement clinker [J]. Environmental Science and Pollution Research, 2018, 25(8): 7600-7607

[13] Li Y-c, Min X-b, Chai L-y, et al. Cotreatment of gypsum sludge and Pb/Zn smelting slag for the solidification of sludge containing arsenic and heavy metals [J]. Journal of Environmental Management, 2016, 181: 756-761

[14] Ke Y, Min X-b, Chai L-y, et al. Sulfidation behavior of Zn and ZnS crystal growth kinetics for Zn(OH)₂-S-NaOH hydrothermal system [J]. Hydrometallurgy, 2016, 161: 166-173

[15] Ke Y, Chai L-y, Min X-b, et al. Sulfidation of heavy-metal-containing neutralization sludge using zinc leaching residue as the sulfur source for metal recovery and stabilization [J]. Minerals Engineering, 2014, 61: 105-112

[16] Gu J-h, Yang J-h, Dou Z-j, et al. Ultrahigh surface area porous carbon from catechol rectification residue with excellent adsorption capacity for various organic pollutants [J]. Separation and Purification Technology, 2022, 284: 120244

[17] Yu Y, Hu J-h, Li Y-k, et al. A new method for simultaneous separation and solidification of arsenic from arsenic-bearing gypsum sludge using waste carbon cathodes [J]. Separation and Purification Technology, 2022, 291: 120656

[18] Li X, Zhu X, Qi X-j, et al. Pyrolysis of arsenic-bearing gypsum sludge being substituted for calcium flux in smelting process [J]. Journal of Analytical and Applied Pyrolysis, 2018, 130: 19-28

[19] Hudson-Lamb D L, Strydom C A, Potgieter J H. The thermal dehydration of natural gypsum and pure calcium sulphate dihydrate (gypsum) [J]. Thermochimica Acta, 1996, 282–283: 483-492

[20] Ma X-l, Tan H-b, Dong F-q, et al. Influence of carbon and pyrite on desulfurization behavior of red gypsum at high temperature [J]. Journal of Sustainable Metallurgy, 2022, 8(1): 409-418

[21] Tao D, Chen S, Parekh B K, et al. An investigation of a thermochemical process for conversion of gypsum and pyrite wastes into useful products [J]. Advances in Environmental Research, 2001, 5(3): 277-284

[22] Tan H-b, Ye M, Su X-m, et al. Elemental sulfur recovery from FGD gypsum and calcium cyclic utilization in coal-fired power plants [J]. Journal of Thermal Analysis and Calorimetry, 2022, 147(24): 14115-14121

[23] Song W-m, Zhou J-n, Wang B, et al. Production of SO₂ gas: New and efficient utilization of flue gas desulfurization gypsum and pyrite resources [J]. Industrial & Engineering Chemistry Research, 2019, 58(44): 20450-20460

[24] Zagoruiko A. Mathematical modelling of Claus reactors undergoing sulfur condensation and evaporation [J]. Chemical Engineering Journal, 2002, 87(1): 73-88

[25] Zhang T-f, Han J-w, Liu W, et al. Recovery of zinc and extraction of calcium and sulfur from zinc-rich gypsum residue by selective reduction roasting combined with hydrolysis [J]. Journal of Environmental Management, 2023, 331: 117256

[26] Zhang L, Zhang L, He Y. The process and application of oxygen-enriched air side blown smelting of lead-zinc materials [C]. PbZn 2020: 9th International Symposium on Lead and Zinc Processing, 2020, Cham: Springer 291-299

[27] Zhang Z-t, Dai Xi. Effect of Fe/SiO₂ and CaO/SiO₂ mass ratios on metal recovery rate and metal content in slag in oxygen-enriched direct smelting of jamesonite concentrate [J]. Transactions of Nonferrous Metals Society of China, 2020, 30(2): 501-508

[28] Li Y, Chang C, Jie Y-f, et al. Thermodynamic phase conversion mechanism on copper-cobalt slag cleaning process using gypsum wastes as sulfurizing agent [J]. Journal of Sustainable Metallurgy, 2021, 7(4): 1643-1653

[29] GB/T 5484-2012. Methods for chemical analysis of gypsum [S]. (in Chinese)

[30] Lü J-f, Jin Z-n, Yang H-y, et al. Effect of the CaO/SiO₂ mass ratio and FeO content on the viscosity of CaO-SiO₂-12wt%ZnO-3wt%Al₂O₃ slags [J]. International Journal of Minerals, Metallurgy, and Materials, 2017, 24(7): 756-767

[31] Zhang G-h, Chou K C, Xue Q-g, et al. Modeling viscosities of CaO-MgO-FeO-MnO-SiO₂ molten slags [J]. Metallurgical and Materials Transactions B, 2012, 43(1): 64-72

[32] Zhang L-ru. Modern lead metallurgy [M], 2013, Changsha: Central South University Press (in Chinese)

[33] Ruan B-w, Jiao F, Liu W, et al. Utilization and detoxification of gypsum sludge by replacing limestone in reduction smelting of high lead slag [J]. Journal of Central South University, 2023, 30(4): 1145-1157

[34] GB5085.3–2007. Identification standards for hazardous wastes identification for extraction toxicity [S]. (in Chinese)